1. Field of the Invention
This invention relates in general to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, this invention involves a male hydraulic coupling member having an improved flow port.
2. Description of Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member with sealed fluid passageways connecting therebetween. The female member generally is a cylindrical body with a relatively large diameter longitudinal bore at one end and a relatively small diameter longitudinal bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore seals and slidingly engages the male member of the coupling. The male member includes a cylindrical portion at one end having an outer diameter approximately equal to the diameter of the large bore of the female member of the coupling. The male member also includes a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical portion of the male member is inserted into the large bore of the female member, according to various embodiments of the device, fluid flow is established between the male and female members. Couplings of this type are shown in U.S. Pat. No. 4,694,859 to Robert E. Smith, III and other patents owned by National Coupling Company, Inc. of Stafford, Tex.
In undersea drilling and production applications, the male member of the coupling may be connected to a manifold plate or other securement at a subsea location at the inside or outside of a well bore. The female members, which also may be secured to a manifold plate, are moved into position over the male members and then lowered onto the male members by a diver or subsea vehicle. When the female members are positioned on the male members, hydraulic fluid flow typically is from the female member to the male member of each coupling. In some cases, only the female member of the coupling has a poppet valve.
The poppet valve typically includes a conical valve face which seats, in the closed position, against a valve seat in the coupling member. The poppet valve opens to allow fluid flow, and closes against the valve seat within the bore to arrest the flow. Generally, the poppet valve is spring-biased to the closed position. The valve may include a valve actuator which may be a nose or stem extending from the apex of the valve face along the longitudinal axis of the poppet valve.
In the couplings of U.S. Pat. No. 4,694,859, for example, hydraulic fluid flows longitudinally between the male and female coupling members. A number of different improvements and variations have been introduced in the configuration of flow ports and flow passages in couplings used for undersea applications. Some undersea hydraulic couplings are pressure balanced, for example, which may be achieved by hydraulic flow through aligned radial flow passages in the coupling members. The radial flow passages are generally perpendicular to the longitudinal axis of the coupling, so hydraulic pressure tending to separate the coupling members is significantly reduced. In the male coupling members, radial passages typically extend from the central bore outward to the cylindrical outer surface of the probe. Examples of pressure balanced couplings are shown in U.S. Pat. Nos. 4,754,780, 5,099,882, and 4,832,080 to Robert E. Smith III, assigned to National Coupling Company, Inc.
Male undersea hydraulic coupling members also may include flow ports that are angled to prevent ingress of debris when the coupling members are disconnected. Frequently, well bores in which the couplings are positioned are full of debris. The male member, which remains subsea when the coupling is disconnected, is subject to debris accumulating in flow passages. The debris may contaminate the hydraulic fluid or cause wear to the seals and sealing surfaces in hydraulic couplings and hydraulic systems. To reduce or eliminate this problem, couplings such as those of U.S. Pat. No. 5,692,538 to Robert E. Smith, III have utilized angled flow ports that prevent ingress of debris into the hydraulic lines.
In the past, radial or angled flow passages in male undersea hydraulic coupling members had a tendency to scrape or rub the metal and/or elastomeric seals in the female coupling members when the male members were engaged to or disengaged from the female coupling members. This could damage the sealing surfaces of metal and/or elastomeric seals, especially for couplings that are repeatedly connected and disconnected. Damage to the sealing surfaces between the male and female coupling members, as a result of repeated engagement and disengagement of the coupling members, could then result in the risk of leakage or loss of hydraulic fluid in the subsea environment.
There also is a need for undersea hydraulic couplings that allows seawater to bleed from or into the receiving chamber of the female member during coupling and/or uncoupling. When the male member is engaged to the female member, trapped seawater in the receiving chamber tends to block or resist full and complete engagement of the male member therein. When the male member is disengaged, this can result in a vacuum, increasing the separation force necessary to apply thereto.
The present invention resides in a male undersea hydraulic coupling member having improved flow ports to prevent or reduce damage to radial seals in the female coupling member. At the outwardly facing end of each flow port, a concave surface is provided that temporarily disengages all or a portion of the radial metal seal(s) in the female coupling member. The concave surface may comprise a plurality of dish-shaped surfaces, with each dish-shaped surface adjacent the outwardly facing end of a flow port. Or, the concave surface may comprise a channel encircling the probe section adjacent the outwardly facing ends of the flow ports. When a radial seal is briefly disengaged, the concave surface allows seawater to bleed from or into the receiving chamber during connection or disconnection of the male and female coupling members.